The group analysed 200 studies from 55 countries, on every continent except Antarctica, and found seafood fraud present in almost every investigation.

The only place where fraud wasn’t found was in Tasmania, though that was only because some mislabelling – such as calling hake ‘smoked cod’ – is allowed there under Australian regulation.

They also found that incorrect labelling affects every sector of the seafood supply chain, including: retail, wholesale, distribution, import and export, packaging and processing, and landing.

The most common instance of seafood fraud was the farmed Asian catfish. In 141 instances, it was found to have been sold in places of 18 different types of more expensive fish around the world, but mostly for perch, grouper and sole. Instances of farmed Asian catfish fraud was found in the US and Canada, Europe, Brazil and India.

In case after case, cheaper or less desirable fish were mislabeled as more expensive varieties.This hurts consumers as well as honest fishermen and businesses
– Oceana

Beth Lowell, senior campaign director for Oceana and one of the authors of the report, said: “It is likely that the average consumer has eaten mislabelled fish for sure.

“You’re getting ripped off, while you enjoyed your meal you’re paying a high price for a low fish.”

The report also found that more than half (58 per cent) of the samples substituted for other fish often posed a health risk to consumers.

In South Africa, king mackerel – which has high levels of mercury – was incorrectly sold as barracuda and wahoo, while in New York blueline tilefish – which is on the do-not-eat list thanks to its mercury content – was sold as halibut or red snapper.

Only full-chain traceability for all species will ensure our seafood is safe, legally caught and honestly labelled
– Dr Kimberly Warner

There were also instances of endangered fish being sold. In Southern California two sushi chefs were charged with selling endangered whale meat as fatty tuna to customers, while in Brazil 55 per cent of shark samples tested were found to be the largetooth sawfish, a species considered critically endangered.

The report concluded that the majority of studies (65 per cent) include clear evidence of an economic motivation for deliberate seafood mislabelling: “In case after case, cheaper or less desirable fish were mislabeled as more expensive varieties.

“This hurts consumers as well as honest fishermen and businesses.”

Dr Kimberly Warner, a senior scientist at Oceana and another author of the report said changes need to be made in the global seafood industry: “Because illegal caught seafood, some caught or processed with slave labour, could be making its way onto our dinner plates disguised as legal catch, it is doubly important to improve transparency and accountability in the global seafood supply chain.

“The increased traceability and consumer labelling efforts in the EU point us to solutions that really do work to decrease seafood fraud, particularly in sectors and products covered by these legal provisions.

“The U.S. government should take note and issue the strongest possible final traceability rule. Only full-chain traceability for all species will ensure our seafood is safe, legally caught and honestly labelled.”